There have so far been proposed various types of differential apparatuses one of which comprises a differential case for accommodating a differential mechanism therein, a differential carrier for rotatably supporting the differential case, a carrier cover attached to the differential carrier, a ring gear secured to the differential case, a drive pinion held in mesh with the ring gear, and a pair of bearings for rotatably supporting shaft portions of the drive pinion (See, for example, Patent Document 1).
The above mentioned differential apparatus is constructed in such a manner that the bearings to rotatably support the drive pinion are positioned in a pinion shaft chamber formed in the differential carrier. In addition, the differential carrier is formed with a lubricant oil introduction chamber for receiving lubricant oil stirred up by the ring gear. The lubricant oil introduction chamber is positioned in the pinion shaft chamber to be offset with respect to the ring gear. The bottom portion of the lubricant oil introduction chamber extends downwardly from the top part of the pinion shaft chamber, while the bottom portion of the lubricant oil introduction chamber has a lubricant oil hole formed therein, the lubricant oil hole extending from the lubricant oil introduction chamber to the pinion shaft chamber to be slanted with respect to the horizontal plane allowing the center axis of the drive pinion to pass thereon. Here, the inner side surface of the lubricant oil introduction chamber is inclined with respect to the horizontal plane so that the lubricant oil introduced in the introduction chamber gathers toward the lubricant oil hole.
The above mentioned construction of the conventional differential apparatus enables the lubricant oil in the differential carrier to be stirred up by the ring gear and then introduced into the lubricant oil introduction chamber with a centrifugal force caused by the lubricant oil. The lubricant oil introduced into the lubricant oil introduction chamber flows downwardly along the slanted inner side surface of the lubricant oil introduction chamber with a gravity force of the lubricant oil, before reaching the lubricant oil hole formed on the bottom portion of the lubricant oil introduction chamber. The lubricant oil is then introduced along the inner side surface of the lubricant oil introduction chamber, passes through the lubricant oil hole, and flows into the pinion shaft chamber from the lubricant oil hole. This results in the fact that some extent amount of lubricant oil is supplied to the pinion shaft chamber so that the bearings for supporting the pinion shaft therefore come to be lubricated.